1. Field of the Invention
This invention relates to a method, program, and apparatus for designing a semiconductor device and, more particularly, to a method, program, and apparatus for designing a semiconductor device which insert a dummy pattern between design patterns.
2. Description of the Related Art
The technology of inserting a dummy pattern between design patterns is now essential to controlling variations in the flatness of the surface of a chip or the width of design patterns in semiconductor devices caused by non-uniformity of design pattern density. Therefore, design tools for designing semiconductor devices in which a dummy pattern has been inserted have been provided.
With aluminum wirings, for example, side wall protection films are formed on the side walls of wiring patterns. If wiring pattern density is non-uniform, then side wall protection films of different thicknesses will be formed in the etching process. Accordingly, to make wiring pattern density uniform, design is made by the use of a design tool so that a dummy pattern will be inserted between wiring patterns.
With copper wirings, if wiring pattern density is non-uniform, then the center of a wiring pattern will become depressed at chemical mechanical polishing (CMP) time. Accordingly, to make wiring pattern density uniform, design is made by the use of a design tool so that a dummy pattern will be inserted between wiring patterns.
With conventional design tools, however, a dummy pattern is inserted between design patterns so that dummy pattern density and design pattern density on the entire semiconductor chip will be desired values. Therefore, there may exist an area on a semiconductor chip where a dummy pattern is not inserted, resulting in non-uniform pattern density.